Process for increasing the emission in the ultra-violet region from mercury-vapor lamps



May 29, 1928. 1,671,109

I H. GEORGE PROCESS FOR INCREASING THE EMI SION IN THE ULTRA VIOLETREGION FROM MERCURY VAPOR LAMPS Filed May 26, 1925 I n venfof Henri Gear5 13 his fillTorneyg Patented May 2 9, 1928. v I

UNITED STATES v 1,671,109- PATENT oF-FicE.

HENRI GEORGE, OI PARIS, FRANCE, ASSIGNOB, BY MESN E ASSIGNMENTS, TOHANOVIA GHEKIOAL & MANUFACTURING COMPANY, 01 NEWARK, NEW JERSEY, ACORPORA- TI ON OF-NEW JERSEY.

PROCESS E03 INCREASING 'rnn EMISSION in mm ULTRA-VIOLET moron r301:

unncun'rivaroa Lmrs.

Application filed Kay 26, 1925, Serial N9. 82,959, and in France Kay 80,1924.

The present invention relates to a process and .apparatus for increasingthe emission in the ultra-violet region from mercury vapor lamps.

It is known that mercury vapor lamps with quartz envelopes constitute asource of ultra-violet rays giving an excellent efliciency. It islikewise known that such lamps can be supplied directly with alternatingcurrent, by keeping within the conditions defined in the French PatentNo. 493,026, dated 24th April, 1918. A comparison of the spectra.emitted in analogous conditions by mercury vapor lamps suppliedrespectively with continuous current and with alternating current,"shows that by varying the voltage and frequency in the latter case thedistribution of the energy in the spectrum is varied to a great extent.The applicant has ascertained that the higher the voltage and thefrequency of the current supplied, the greater will be the radiation inthe ultra-violet region. Thus, for equal amounts of energy expended, aten-fold increase of certain ultra-violet rays can be obtained when thelam is supplied with alternating current at igh voltage and highfrequency.

This method of supply, which forms the subject of the present invention,has thus for efl'ect to increase the efliciency or yield of the mercuryvapor lamp as regards ultraviolet radiations.

The invention also comprises an apparatus for carrying out this process;the apparatus is characterized by an arrangement and combination ofparts for transforming the alternating currentof the local supply into ahigh frequency current, connected between the current-supply terminalsand the mercury-vapor lamp with quartz wall or envelope.

The accompanying drawing represents d1- a rammatically y way of examplea form 0% construction'of this apparatus.

The mercury vapor lamp consists of a tube 1 in the shape of an invertedU made of transparent silica, connecting two vessels 2, 2; the lattercontain mercury and are fitted with the electrodes 3, fixed in anysuitable manner, as by grinding, sealing, etc. Along the tube 1 there isattachedor fused on a vessel 4, the dimensions of which are calculatedso as to ensure stable operation of the lamp. The tube is preferablyfilled with an inert gas, such as argon or neon,.at a pressure of somecentimetres of mercury; the pressure of this gas has for its object toensure the lighting or starting of the lamp and its operation onalternating current. If

of the local system, and the electrodes 3, 3,

there is interposed the device for transforming the local alternatingcurrent into a high frequency current; this device may consist of theconventional arrangement comprising a transformer 6, inductance 7,capacities 8,

8, and spark-gap 9; the mercury vapor lamp is connected, as shown to theterminals of the inductance 7. It is obvious that any other arrangementmay be used in which the lamp is connected tothe terminals of theinductance of an oscillating circuit.

Apart from the technical advanta e ofthe increased yield, the processdescri e'd presents other advantages of a practical natpre inthe'commonest applications of mercury vapor lamps, namely to scientificand therapeutic uses. are comparatively harmless, the process describedallows of much readier manipulation of the apparatus without fear ofaccidents. Another practical advantage results from the fact that thedevice employed for trans forming the local alternating current intohigh frequency current may be utilized for other purposes, in thelaboratory,: for ex-' ample, for the productionof sparks forspectroscopy, and b medical practitioners, for example, for bigi-frequency treatment, es ecially diathermy; this allows of considera lesaving in the total cost of equipment.

What I claim is:

1-. In combination with a mercury vapor lamp having a quartz envelope,means for increasing. the ultra-violet emission of the lamp comprising asource of high frequency, high voltage current, and means for connectingthe terminals of the lamp to the termi- 86 Since high frequency currentsI nals of saidsource of current so that'the mercury vapor in the lampwill serve as a conductor of the high frequency, high voltage current.

'2. In combination with a mercury vapor lamp having a uartz envelope,means for increasing the u tra-violet emission of the lamp comprising asource of current, means interposed between the lamp and the source ofcurrent for converting the supply'current' into high frequency highvoltage'cur'rent, the terminals of the lamp being so connected to theinterposed means that the mercury vapor in thelamp will serve as aconductor for the high frequency high voltage current.

3.- An apparatus for increasing ultra viowith quartz envelope comprislnga source of current, a high frequenc high voltage oscillating circuitinterpose between the lamp and the source of current, said circuitcomprising the secondary of a transformer in parallel with aninductance, a spark gap, and condensers in series with the inductance,the terminals of the inductance being connected to the terminals of themercury vapor lamp so that the mercury vapor in the lamp Will serve as aconductor of the high frequency high voltage current.

In testimony whereof I have signed my name to this specification. IHENRI GEORGE.

. let ray emission of a mercury vapor lamp

